Although it is mainstream in a conventional technique to place separately a motor and an amplifier for supplying a driving power to the motor, the separate placement type requires a control panel for accommodating the amplifier. In addition, since wiring to connect the motor and the amplifier is required, an amplifier-integrated motor is more advantageous.
In the amplifier-integrated motor, it has been difficult to simultaneously achieve a reduction in the size of an entire motor by a reduction in the volume of an amplifier section to be attached to the motor and a simple assembly structure. Moreover, the amplifier section is formed by a large number of element parts and therefore has a higher failure rate as compared to a motor section. Thus, the amplifier section is desired to have a structure with which the element parts thereof are replaceable.
As a conventional technique, there is disclosed a motor accommodating motor constituent elements in a motor case in which: at least a motor driving circuit substrate and a switching element are accommodated in a module case that forms a part of the motor case to achieve integral formation as a drive circuit module; and the drive circuit module is resin-encapsulated (see Patent Literature 1, for example).